Change the way that underline positions are calculated by delaying using
the "visual" column position until the last possible moment, instead
using the "file"/byte position in the file, and then calculating visual
positioning as late as possible. This should make the underlines more
resilient to non-1-width unicode chars.
Unfortunately, as part of this change (which fixes some visual bugs)
comes with the loss of some eager tab codepoint handling, but the output
remains legible despite some minor regression on the "margin trimming"
logic.
When encountering a single line span that is wider than the terminal, we keep context at the start and end of the span but otherwise remove the code from the middle. This is somewhat independent from whether the left and right margins of the output have been trimmed as well.
```
error[E0308]: mismatched types
--> $DIR/long-span.rs:6:15
|
LL | ... = [0, 0, 0, 0, ..., 0, 0];
| ^^^^^^^^^^^^^...^^^^^^^ expected `u8`, found `[{integer}; 1681]`
```
Address part of #137680 (missing handling of the long suggestion). Fix#125581.
`-Zteach` is perma-unstable, barely used, the highlighting logic buggy and the flag being passed around is tech-debt. We should likely remove `-Zteach` in its entirely.
```
error[E0610]: `{integer}` is a primitive type and therefore doesn't have fields
--> $DIR/attempted-access-non-fatal.rs:7:15
|
LL | let _ = 2.l;
| ^
|
help: if intended to be a floating point literal, consider adding a `0` after the period and a `f64` suffix
|
LL - let _ = 2.l;
LL + let _ = 2.0f64;
|
```
Fix logical error with what text is considered whitespace.
There appears to be a logical issue around what counts as leading white-space. There is code which does a subtraction assuming that no errors will be reported inside the leading whitespace. However we compute the length of that whitespace with std::char::is_whitespace and not rustc_lexer::is_whitespace. The former will include a no-break space while later will excluded it. We can only safely make the assumption that no errors will be reported in whitespace if it is all "Rust Standard" whitespace. Indeed an error does occur in unicode whitespace if it contains a no-break space. In that case the subtraction will cause a ICE (for a compiler in debug mode) as described in https://github.com/rust-lang/rust/issues/132918.
There is a logical issue around what counts as leading white-space.
There is code which does a subtraction assuming that no errors will be reported
inside the leading whitespace. However we compute the length of
that whitespace with std::char::is_whitespace and not
rustc_lexer::is_whitespace. The former will include a no-break space while
later will excluded it. We can only safely make the assumption that no errors
will be reported in whitespace if it is all "Rust Standard" whitespace.
Indeed an error does occur in unicode whitespace if it contains a no-break
space.
Consider comments and bare delimiters the same as an "empty line" for purposes of hiding rendered code output of long multispans. This results in more aggressive shortening of rendered output without losing too much context, specially in `*.stderr` tests that have "hidden" comments.
Use more slice patterns inside the compiler
Nothing super noteworthy. Just replacing the common 'fragile' pattern of "length check followed by indexing or unwrap" with slice patterns for legibility and 'robustness'.
r? ghost
Some `const { }` asserts for #128200
The correctness of code in #128200 relies on an array being sorted (so that it can be used in binary search later), which is currently enforced with `// tidy-alphabetical` (and characters being written in `\u{XXXX}` form), as well as lack of duplicate entries with conflicting keys, which is not currently enforced.
This PR changes it to using a `const{ }` assertion (and also checks for duplicate entries). Sadly, we cannot use the recently-stabilized `is_sorted_by_key` here, because it is not const (but it would not allow us to check for uniqueness anyways). Instead, let's write a manual loop.
Alternative approach (perfect hash function): #128463
r? `@ghost`
On short error format, append primary span label to message
The `error-format=short` output only displays the path, error code and main error message all in the same line. We now add the primary span label as well after the error message, to provide more context.
The `error-format=short` output only displays the path, error code and
main error message all in the same line. We now add the primary span label
as well after the error message, to provide more context.
Change output normalization logic to be linear against size of output
Modify the rendered output normalization routine to scan each character *once* and construct a `String` to be printed out to the terminal *once*, instead of using `String::replace` in a loop multiple times. The output doesn't change, but the time spent to prepare a diagnostic is now faster (or rather, closer to what it was before #127528).
When a suggestion part is for already present code, do not highlight it. If after that there are no highlights left, do not show the suggestion at all.
Fix clippy lint suggestion incorrectly treated as `span_help`.
Scan strings to be normalized for printing in a linear scan and collect
the resulting `String` only once.
Use a binary search when looking for chars to be replaced, instead of a
`HashMap::get`.
